The stats don't lie. Seven of the 20 head coaches at this year's World Cup will be New Zealanders. Nine more are at the helm across Europe's major leagues — France's Top 14, England's Premiership and the Pro14. Eight others — two in Australia — hold the reins in Super Rugby.
Cotter heads the list of domestic top earners on what is believed to be close to €1 million per season ($1.6 million) at Montpellier.
Rennie, with Glasgow, and Lam, at Bristol, are understood to be the highest paid coaches in their respective competitions.
Specialising exclusively in the management of leading coaches, Esportif director Duncan Sandlant is well placed to view the changing landscape.
"There is definitely greater recognition of professional rugby coaches and the difference a quality head coach or assistant can make in terms of performance in an increasingly competitive market, particularly in light of salary cap pressures which don't apply to coaching spend," Sandlant says.
"Like the player market, the coaching market has become increasingly more global and competitive. There are still clubs that believe in the ex-star player being the best way forward as a head coach, which was and still is prevalent in football, but you only have to look at clubs or national rugby unions that have invested in quality professional coaching teams to see the benefits."
This premium demand for Kiwi nous has been created by a track record of success.
Warren Gatland's coaching career took off with three titles at Wasps. Cotter built Clermont into the club they are today. Lam, after being binned by the Blues, achieved what no one thought possible with Connacht. Wayne Pivac, having never made the Super Rugby grade, transformed the Scarlets into Pro14 champions and is now poised to succeed Gatland with Wales next year. Schmidt — another Blues castoff — led the Leinster and Irish golden age.
Such success in all major European rugby nations places Kiwi coaches at the head of the recruitment queue. No other foreign nation has made a comparable mark.
Former Wallabies playmaker Pat Howard enjoyed success at Leicester but few other Australians have made an impact.
Likewise, South Africans. Springboks coach Rassie Erasmus left an impression at Munster but he was there only 18 months and his squad were inspired to play for Anthony Foley following the sudden death of the much-liked assistant coach in Paris.
Elsewhere, Jake White has been underwhelming, while former Lions coach Johan Ackermann is doing a reasonable job with Gloucester.
New Zealand has always recognised the importance of quality coaching.
Sure, the talent base and inherent attacking skills are driving factors but coaching is a major reason why the All Blacks have, to this point at least, enjoyed a consistent edge on the rest of the world.
Like players, though, New Zealand will never be able to compete on coaching salaries.
In recent times, New Zealand has lost Rennie, Lam, Chris Boyd, Todd Blackadder, Jamie Joseph and Tony Brown — all from Super Rugby to big-money contracts. That's a lot of intellectual property.
Three years ago, the gap in earnings was greater than it is now. New Zealand Rugby has made an effort to pay their coaches more and also recruited foreigners in the form of men's sevens coach, Scotsman Clark Laidlaw, and Crusaders assistant Ronan O'Gara.
Yet with the average head coach in Europe pocketing around £250,000 ($471,000), the global value will always be out of reach.
Brown, with Japan, is thought to be one of the highest paid back attack coaches in world rugby, on around $500,000 for his dual roles with the national team and the Sunwolves.
Compare that with New Zealand, and Highlanders head coach Aaron Mauger earns around half that figure.
Money is not everything, of course.
New Zealand's strength lies in its commitment to development which, therefore, comes with security not afforded in Europe. Even those who clearly struggle, the likes of Sir John Kirwan and Tana Umaga at the Blues, were given at least three years to imprint their vision.
Overseas, the coaching profession is fraught from day one. During the past two years, 22 of the 40 head coaches in the Premiership, Pro14 and Top 14 have changed, with four more already known for next season.
Geordan Murphy is the fourth head coach at Leicester Tigers in 21 month.
Sandlant, a qualified lawyer and recently voted among Rugby World's top 50 list of influential people in the game, witnesses these knee-jerk reactions all too often.
"It is really important that coaches are protected as much as possible from a contractual point of view at the outset, as you have unrealistic owners or boards where reality and expectation are not aligned.
"It is very common for owners, CEOs and executive board members, some of whom have limited knowledge of professional sport, making decisions on their head coach based on incorrect information, facts or fans' views on social media.
"The consequences for these coaches can be pretty extreme, with a number not being employed again and, unlike football, they don't get life-changing golden handshakes on the way out. It is an incredibly high risk career, with a number of factors completely outside a coaches' control."
Assessing New Zealand's Super Rugby landscape, it is difficult to envision many jumping into the European guillotine in the coming years.
Highlanders duo Mauger and Mark Hammett, the latter at the Cardiff Blues, have been burned before and are unlikely to return any time soon. John Plumtree's Hurricanes tenure is beginning as he settles into his home town franchise.
Leon MacDonald is the latest to begin the task of turning around the Blues, and he is joined by Tom Coventry, who did not have the roster or support to stop London Irish being relegated.
Tabai Matson, having returned from a brief stint at Bath alongside Blackadder, probably has visions of succeeding Colin Cooper with the Chiefs.
Scott Robertson is the exception. Should he miss out on promotion to the All Blacks next year, Robertson may seek a position in France, though leading the Crusaders is a prime role and one hard to walk away from.
International opportunities will arise post-World Cup but, even then, most major nations have succession plans in place.
Risk and reward must be weighed in every instance, as one wrong move can end a career.
Coaching breakdown
Of the 59 head coaches across top competitions, excluding Japan, 18 are New Zealanders.
World Cup teams: Twenty head coaches, seven New Zealanders — Milton Haig (Georgia), Joe Schmidt (Ireland), Steve Hansen (New Zealand), Steve Jackson (Samoa), Jamie Joseph (Japan), Warren Gatland (Wales), John McKee (Fiji).
Pro14 (14 HC): Three New Zealanders — Kieran Crowley, Dave Rennie, Wayne Pivac. Brad Mooar will be the latest recruit, when Pivac steps up to Wales next year.
Premiership (16 HC/DOR): Three New Zealanders — Todd Blackadder, Pat Lam, Chris Boyd.
Top 14 (15 HC): Three New Zealanders — Vern Cotter, Jono Gibbes, Simon Mannix.
Super Rugby (15 HC): Eight New Zealanders — Leon MacDonald, Colin Cooper, Scott Robertson, Aaron Mauger, John Plumtree, Brad Thorn, Tony Brown, Daryl Gibson.
